When there is a risk of being exposed to an electric arc, for example, when servicing equipment in non-arc-safe distribution plants or electrical switchboards, or when working on high voltage equipment, personnel are recommended to wear arc-approved protective clothing.
What protection does your clothing need to provide during an arc blast?
The plasma clouds, flames, radiation and metal splashes from the electrodes hit the fabric during an arc blast. When this occurs, the fabric must provide sufficient insulation to prevent second-degree skin burns. An effective fabric used in an arc garment must provide shielding against the flame and metal splashes, as well as insulation from the intense heat. The standard IEC 61482-2 includes two test methods, EN 61482-1-1 (open arc) and EN 61482-1-2 (box test). Our garments are certified according to both test methods or one of them.
The garments must cover the whole body. For example, jacket and trousers must be worn together with other personal protective equipment (PPE), including a helmet with protective visor, protective gloves and protective footwear (boots) to achieve the correct level of protection. Layering is very important and will increase protection – if you wear flame retardant underwear underneath your flame retardant garments you are protected for even better.
ARC TEST IEC/EN 61482-1-1:2009 – OPEN ARC TEST
EN 61482-1-1: Protective clothing against the thermal hazards of an electric arc. Part 1-1 – Method 1: Determination of the arc rating (ATPV or EBT50) of flame resistant material or clothing.
ATPV and EBT are both evaluated in the same test, an open arc test (EN 61482-1-1/ASTM F1959). If the material has more thermal insulation value than arc tensile strength in resistance to heat, then it will break open first. If the opposite is true, the material will allow burns before it breaks open. The lowest value is the one that is used in the marking of the garments. Neither is better than the other. In essence, EBT fabrics are typically more insulating than they are strong and ATPV materials are stronger than they are insulating. You should never make a clothing protection decision based on the fact that clothing has achieved an ATPV or EBT rating. They are regarded as functional equivalents. Arc Thermal Performance Value (ATPV) is the incident energy on a material that results in a 50% probability that sufficient heat transfer through the specimen is predicted to cause the onset of second-degree burn injury based on the Stoll Curve. The higher the value, the better the protection. Energy Break open Threshold: (EBT) is the incident energy on a material that results in a 50% probability of break open. Break open is defined as any open area at least 1.6 cm². The higher the value, the better the protection. Both ATPV and EBT can be tested on single or multiple layers of material. When you test multiple layers, you will achieve a higher value then if the fabrics were tested separately because air trapped between the fabrics also has an insulating and protective effect. Heat Attenuation Factor (HAF) is the measurement of the percentage of energy that is blocked by the material or material system.
ARC TEST IEC/EN 61482-1-2:2014 – BOX TEST
EN 61482-1-2: Protective clothing against the thermal hazards of an electric arc. Part 1-2 – Method 2: Determination of arc protection class of material and clothing by using a constrained and directed arc (box test).
The garments are tested and evaluated in two classes in the same test; a box test. (Voltage: 400 V, Duration: 500 ms, Frequency: 50Hz or 60Hz).
Class 1 = 4 kA (arc energy 168 kJ)
Class 2 = 7 kA (arc energy 320 kJ)
The result is approved or not approved and in the test reports the design is also commented on i.e. that the zip still works after exposure.